This is too weird.
Just out of curiosity I hooked my Fender Super Champ xd to my Peavey 6505 (preamp out of xd to effects return of 6505) and damned if it isn't the best tone I've gotten in years!
I still don't have a proper cabinet so my other guitarist Greg was gracious enough to loan me his homemade 2x12 with unknown speakers (he made it about a decade ago and doesn't remember) and I wasn't impressed by the 6505 with it. Just didn't have any punch and sounded "hollow". Try as I might, I could not dial in the tone I was looking for. Not to mention it was loud as hell!
Using the xd as a preamp, this setup will kick your ass even with the volume (xd) on 3! It sounds HUGE!
None of the controls on the 6505 except the presence and resonance work, everything is controlled by the xd.
I cannot wait until I run this through a 4x12.
I must admit, the xd sitting on top of the 6505 sitting on top of the 2x12 looks pretty retarded, but with the tone I'm getting I'm finding it really hard to care.